Ultrastructural scoring of skin biopsies for diagnosis of vascular Ehlers–Danlos syndrome

Abstract

Vascular Ehlers-Danlos syndrome (vEDS) results from a mutation in the gene encoding alpha-1, type III pro-collagen (COL3A1) and confers fragility to skin, ligament and vascular tissue. We tested the value of skin biopsy for diagnosis of vEDS through an ultrastructure scoring procedure. Study design was a multicentric, case-control, blinded trial consisting of two phases: phase 1 was to identify an ultra-structure score providing the best discriminative value for vEDS and phase 2 was to replicate this result in a different population. We enrolled 103 patients, 66 cases defined through the revised nosology for Ehlers-Danlos syndromes and 37 control subjects selected from patients referred for other pathologies. Ultrastructure of extracellular matrix was read by three to five experienced pathologists blinded for diagnosis. We used the receiver operating curves and logistic regression analysis for ranking ultrastructure scores. We created a detailed description of lesions observed in vEDS patients with 27 items (coded 0 or 1). In the phase 1 (17 cases and 20 controls), abnormal fibroblast shape, presence of lysosomes in the fibroblast and abnormal basal lamina were found to be independent discriminative items. Addition of these three items (defining an ultrastructure score) had the best diagnosis value (area under the curve (AUC) = 0.96). In the phase 2 (49 cases, 17 controls), ultrastructure score provided odds ratio of 9.76 (95 % CI 2.91-32.78), and AUC of 0.90. The ultrastructure score of skin biopsy has predictive value for the diagnosis of vEDS. Presence of two or more signs (either abnormal fibroblast, presence of lysosomes in the fibroblast or abnormal basal lamina) is very evocative of vEDS.

Electron microscopy in the diagnosis of Ehlers–Danlos syndromes: correlation with clinical and genetic investigations

“…Interestingly, there was a considerable overlap in biopsy report features for different EDS subtypes. We did not identify TEM findings that were associated with a specific subtype of EDS and we could not confirm a previous report of findings that included duplication of the lamina densa associating specifically with vEDS . Modifying language was often used to differentiate findings, indicating that a degree of severity influenced the conclusion.…”

“…We did not identify TEM findings that were associated with a specific subtype of EDS and we could not confirm a previous report of findings that included duplication of the lamina densa associating specifically with vEDS. 16 Modifying language was often used to differentiate findings, indicating that a degree of severity influenced the conclusion. This emphasizes the clinical skill and experience required to report and classify findings from TEM biopsies.…”

“…Structural examination using transmission electron microscopy (TEM) or light microscopy of a skin biopsy sample has been used as a diagnostic tool prior to, and in combination with, molecular diagnosis of EDS . There are several abnormal findings on TEM that have been reported in the literature to be indicative of a monogenic type of EDS.…”

“…Structural examination using transmission electron microscopy (TEM) or light microscopy of a skin biopsy sample has been used as a diagnostic tool prior to, and in combination with, molecular diagnosis of EDS. [14][15][16][17][18] There are several abnormal findings on TEM that have been reported in the literature to be indicative of a monogenic type of EDS. These have been identified as: (i) duplication of the lamina densa; 16 (ii) collagen flowers; (iii) variable diameter of collagen fibrils; (iv) disorganization, distortion or kinking of collagen fibres; and (v) other dermal structures including elastic fibres and fibroblasts (Figs 1-4).…”

“…[14][15][16][17][18] There are several abnormal findings on TEM that have been reported in the literature to be indicative of a monogenic type of EDS. These have been identified as: (i) duplication of the lamina densa; 16 (ii) collagen flowers; (iii) variable diameter of collagen fibrils; (iv) disorganization, distortion or kinking of collagen fibres; and (v) other dermal structures including elastic fibres and fibroblasts (Figs 1-4). Many studies describing the electron microscopy findings were published prior to routine genetic testing and molecular diagnosis.…”